Warning: Your Activity Tracker May Be Bad for Your Health

Many health wearables set exercise and diet targets that aren't based on scientific evidence or the wearer's capabilities.

Mike Collins was an avid runner. After completing five half-marathons, he decided to buy a running watch, thinking that being able to track heart rate, pace and distance would help him break the 1-hour-50-minute mark in his next race. But the watch actually had the opposite effect. “Suddenly, I was overthinking it all – picking up the pace when I wasn’t ready or slowing down when I should have kept pushing,” he says. “All in the name of numbers on my wrist.”

A growing number of watches, bands, patches and garments are on the market, claiming to provide helpful feedback on food intake, movement, sleep, sweat, stress levels and more. Consumers are eating it up: According to a 2013 Pew report, 60 percent of U.S. adults track their diet, exercise routine or weight, and a 2017 study found that over 40 percent have used a wearable health tracker. Worldwide, sales of wearable devices are expected to grow by 20 percent each year over the next five years.

Those in favor of tracking devices argue that making people aware of their patterns around food, exercise, sleep or stress can then help users take action to improve their health. And there is valid research supporting that simply tracking your habits can inspire healthy behavior change. But for some people, this compulsive self-quantification may be doing more harm than good.

Case in point: The summer Jessica Cording got her first steps tracker, a friend added her to a group of people who competed against each other for the most daily steps. The competitive social aspect became unhealthy for the New York City-based registered dietitian, who ended up with a hamstring injury.

Another problem with many wearables is that they use one-size-fits-all targets (like a goal of taking 10,000 steps per day), which aren’t necessarily based on scientific evidence or easy for non-health professionals to interpret for themselves. As a result, the devices can lead to injury if the activity type or amount isn’t something a person is physically capable of doing, or if the device data cause them to push themselves too far.

Compulsively tracking health data can also have negative effects on mental health, as it did for me. What started as a desire to lose a few pounds by calorie tracking in high school quickly became obsessive. I second-guessed everything I ate, beat myself up if I ate more than what I was “prescribed,” avoided social activities and over-exercised – even if that meant subsisting on less than five hours of sleep a night. On the food and fitness tracking front, my numbers looked great. But inside, I was a mess.

While I was able to avoid spiraling into an eating disorder, others are not so lucky. Rachael Hartley, a registered dietitian nutritionist with a private practice in Columbia, South Carolina, for one, has worked with plenty of clients whose disordered patterns stemmed from tracking devices. They often don’t realize their behaviors are problematic because they’re so common. “I’ve worked with more than a few clients who started tracking food, calories and/or macros either out of curiosity or to lose weight,” Hartley says, adding that “it’s quickly gotten out of control and led to disordered eating and food obsessions.”

Melissa R. Burton, a registered dietitian nutritionist in Los Angeles, also finds trackers can drive mental health concerns. “Using activity trackers leads to people judging themselves for meeting or not meeting a goal, and puts them on a fast track to disordered eating, excessive exercise and orthorexia,” she says. “We have become a world that is all about quantifying every aspect of our lives in order to feel worthy. The message that you are not enough until you reach your goal creates a drive beyond motivation to a level of obsession.”

Tracking your food can also make it hard to listen to your body. When you’re so focused on the numbers, it’s easy to ignore internal cues like hunger, fullness and what foods make you feel good. “Calorie counting creates an illusion of control; a false narrative that a numeric equation has more wisdom than your internal body cues,” says Jamie Lee, a registered dietitian nutritionist in Portland, Oregon. “It reduces food down to its energy content, ignoring other aspects of eating that bring joy and well-being.”

Not only that, but trackers don’t even seem to work well if better nutrition is what you’re after.”By focusing on numbers, I find that people often turn to packaged foods because they are easier to track,” Hartley says. “Plus, most online trackers underestimate energy needs pretty significantly. It’s much more accurate to listen to your body’s hunger and fullness cues to figure out how much you need to eat.”

It’s even possible for your wearable device to give you a sleep disorder. A study in the Journal of Clinical Sleep Medicine reported an increase in the number of people concerned with their sleep duration and quality after using tracking devices to record their sleep. This anxiety about getting proper sleep, in turn, led to further insomnia. This sleep disorder even has a name: “orthosomnia,” meaning a harmful preoccupation with achieving perfect sleep (similar to orthorexia, an unhealthy preoccupation with healthy eating). The study also reported that the science isn’t there yet to support most of these tracking devices’ ability to measure and improve sleep.

I discovered this challenge firsthand. After struggling with my sleep for several months, a friend recommended I try a popular sleep tracking app to see if I could pinpoint any variables that may have been contributing to my poor sleep. Within just a few days, I realized the app was going to be more harmful than helpful. Not only was I unable to fully understand what the pretty sleep graphs meant, but I also grew discouraged when the app didn’t match how I felt. If I felt I slept great and my body felt great, why was I going to let an app make me feel poorly?

Data can be useful to a point. But as we become overly fixated on numbers, and get preoccupied counting everything and anything, we risk losing track of what really counts. If your health data tracking is coming at the expense of your stress levels, your social life or your relationships with your friends and family, you can hit all the numbers you want and still not be healthy.

“Much of the joy of running and training is finding your ‘runner’s high.’ It’s finding peace on your path, adjusting your pace to your body’s needs that particular day, and enjoying the process,” Collins says. “Having the ability to look down at your heart rate, distance and pace takes all that away.”